Fashion Terms — the Apparel Search fashion terminology directory
Waterproofing is the process of making an object waterproof or water-resistant so it resists the ingress of water under specified conditions; for apparel it can happen at the fabric level or the garment level. Waterproof fabrics are inherently resistant, or treated to become resistant, to penetration by water and wetting — natural or synthetic fabrics laminated to or coated with rubber, polyvinyl chloride (PVC), polyurethane (PU), silicone elastomer, fluoropolymers or wax. Waterproof/breathable fabrics resist liquid water passing through while allowing water vapor to pass, which is why they are used in rainwear, outdoor sports clothing and tents.
What is waterproofing? Waterproofing is the process of making an object or structure waterproof or water-resistant so that it remains relatively unaffected by water. In other words, it helps an object with resisting the ingress of water under specified conditions. Waterproofing is important to many industries, but here we will discuss its relevance for fabrics, apparel & footwear.
When thinking about waterproofing in regard to garments, it is important to consider that waterproofing techniques can take place at the fabric or garment level (or steps taken regarding the fabric and steps taken when sewing the garments).
Waterproof fabrics are fabrics that are inherently, or have been treated to become, resistant to penetration by water and wetting.
The term "waterproof" refers to conformance to a governing specification and specific conditions of a laboratory test method. They are usually natural or synthetic fabrics that are laminated to or coated with a waterproofing material such as rubber, polyvinyl chloride (PVC), polyurethane (PU), silicone elastomer, fluoropolymers, and wax. Treatment could be either of the fabric during manufacture or of completed products after manufacture, for instance by a waterproofing spray. Examples include the rubberized fabric used in Mackintosh jackets or sauna suits.
Waterproof/breathable fabrics resist liquid water passing through, but allow water vapour to pass through. Their ability to block out rain and snow while allowing vapour from sweat to evaporate leads to their use in rainwear, waterproof outdoor sports clothing, tents, and other applications.
Some garments are designed to give greater protection against rain. For example, raincoats and rain boots are specifically designed & manufactured to assist the wearer with staying dry.
Why do we need waterproof textiles? Go outside in the rain without an umbrella and you may better understand the need for waterproofing.
Typical descriptions are "showerproof", "water resistant", and "waterproof".
Waterproof garments specify their hydrostatic rating, ranging from 1,500 for light rain, to 20,000 for heavy rain. Waterproof garments are intended for use in weather conditions which are often windy as well as wet, and are often also wind resistant.
Snow boots & snow pants are also best if water resistant.
Methods of making fabric water resistant:
Durable water repellent, or DWR , is a coating added to fabrics at the factory to make them water-resistant (hydrophobic).
Most factory-applied treatments are fluoropolymer based; these applications are quite thin and not always effective. Durable water repellents are commonly used in conjunction with waterproof breathable fabrics such as Gore-Tex to prevent the outer layer of fabric from becoming saturated with water. This saturation, called 'wetting out,' can reduce the garment's breathability (moisture transport through the breathable membrane) and let water through. As the DWR wears off over time, re-treatment is recommended when necessary. Many spray-on and wash-in products for treatment of non-waterproof garments and re-treatment of proofed garments losing their water-repellency are available from sources of sporting apparel. Older methods for factory application of DWR treatments involve applying a solution of a chemical onto the surface of the fabric by spraying or dipping.
Some researchers have suggested that the use of PFAS's in water-repellent clothing is over-engineering, and comparable performance can be achieved using specific silicon- and hydrocarbon-based finishes.
You might want to also learn about lanolin which is extracted from wool.
The fabric conforms to a governing specification under specific laboratory test conditions and resists penetration by water and wetting — either inherently, or because it has been laminated or coated with a waterproofing material such as rubber, PVC, polyurethane, silicone elastomer, fluoropolymers or wax.
It blocks liquid water — rain and snow — from passing through, but allows water vapor from sweat to pass out and evaporate. That combination is what makes it suitable for rainwear and outdoor sports clothing, where a fully sealed fabric would trap perspiration inside.
The most common treatment in the early 2000s was C8 fluorocarbon-based textile finishes applied during manufacture. Environmental and health concerns led to a transition to C6 fluorocarbon-based finishes and to alternatives such as solvent-free processes that polymerize hydrocarbon chains on the fabric surface.